Impact of an active video game on healthy children’s physical activity

OBJECTIVE: This naturalistic study tests whether children receiving a new (to them) active video game spontaneously engage in more physical activity than those receiving an inactive video game, and whether the effect would be greater among children in unsafe neighborhoods, who might not be allowed to play outside.

METHODS: Participants were children 9 to 12 years of age, with a BMI >50th percentile, but <99th percentile; none of these children a medical condition that would preclude physical activity or playing video games. A randomized clinical trial assigned children to receiving 2 active or 2 inactive video games, the peripherals necessary to run the games, and a Wii console. Physical activity was monitored by using accelerometers for 5 weeks over the course of a 13-week experiment. Neighborhood safety was assessed with a 12 item validated questionnaire.

RESULTS: There was no evidence that children receiving the active video games were more active in general, or at anytime, than children receiving the inactive video games. The outcomes were not moderated by parent perceived neighborhood safety, child BMI z score, or other demographic characteristics.

CONCLUSIONS: These results provide no reason to believe that simply acquiring an active video game under naturalistic circumstances provides a public health benefit to children.

The effects of the late 2000s global financial crisis on Australia's construction demand

An accurate measurement of the impacts of external shocks on construction demand will enable construction industry policymakers and developers to make allowances for future occurrences and advance the construction industry in a sustainable manner. This paper aims to measurethe dynamic effects of the late 2000s global financial crisis on the level of demand in the Australian construction industry. The vector error correction (VEC) model with intervention indicators is employed to estimate the external impact from the crisis on a macro-level construction economic indicator, namely construction demand. The methodology comprises six main stages to produce appropriate VEC models that describe the characteristics of the underlying process. Research findings suggestthat overall residential and non-residential construction demand were affected significantly by the recent crisis and seasonality. Non-residentialconstruction demand was disrupted more than residential construction demand at the crisis onset. The residential constructionindustry is more reactive and is able to recover faster following the crisis in comparison with the non-residential industry. The VEC model with intervention indicators developed in this study can be used as an experiment for an advanced econometric method. This can be used to analyse the effects of special eventsand factors not only on construction but also on other industries.

Students' intercultural development through language learning in Vietnamese tertiary education: a case study on the use of film as an innovative approach

Vietnam's open-door policy, its socialist-oriented market economy, recent growth in cross-border education and skills mobility, regionalisation and globalisation have created an increasing demand for Vietnamese graduates to develop not only their English language but also their intercultural competence. This paper discusses the issue of student intercultural learning and development in the Vietnamese English as a foreign language (EFL) class. Especially, it addresses the use of film as an innovative approach to engage Vietnamese students in intercultural learning and development in the EFL classroom. The study reported in this paper draws on rich sources of data which include in-depth interviews with students, student reflective journals and video-recorded class observations at a university in central Vietnam. Overall, five key themes relating to student intercultural learning through film have been identified in this study. These include enhancing knowledge about cultural differences, engaging in cross-cultural comparison, breaking cultural stereotypes, immersing students in authentic learning and living in the world of ‘other’ culture and the integrated mode of intercultural language learning. The study is a significant contribution to scholarly research on the use of media objects to enhance student intercultural learning in language classrooms in developing countries.

Does supply always come on the heels of demand? Matches and mismatches in e-learning

Developing sustainable e-learning requires a better understanding of the perceptions and preferences of e-learning providers and e-learners on the four crucial dimensions for elearning success including pedagogies, technologies, learning resources and management of learning resources. There is, however, little research on evaluating whether these critical dimensions are perceived as critical by e-learning providers and e-learners. To address this issue, this study investigates the gap between e-learners’ and e-learning providers’ perceptions and preferences on these critical dimensions for e-learning effectiveness. Such an investigation paves the way for developing appropriate measures to reduce the gap between the supply and the demand for sustainable e-learning.

A review on artificial intelligence based load demand forecasting techniques for smart grid and buildings

Electrical load forecasting plays a vital role in order to achieve the concept of next generation power system such as smart grid, efficient energy management and better power system planning. As a result, high forecast accuracy is required for multiple time horizons that are associated with regulation, dispatching, scheduling and unit commitment of power grid. Artificial Intelligence (AI) based techniques are being developed and deployed worldwide in on Varity of applications, because of its superior capability to handle the complex input and output relationship. This paper provides the comprehensive and systematic literature review of Artificial Intelligence based short term load forecasting techniques. The major objective of this study is to review, identify, evaluate and analyze the performance of Artificial Intelligence (AI) based load forecast models and research gaps. The accuracy of ANN based forecast model is found to be dependent on number of parameters such as forecast model architecture, input combination, activation functions and training algorithm of the network and other exogenous variables affecting on forecast model inputs. Published literature presented in this paper show the potential of AI techniques for effective load forecasting in order to achieve the concept of smart grid and buildings.

On the differentiability of the consumer demand function

For strictly quasi concave differentiable utility functions, demand is shown to be differentiable almost everywhere if marginal utilities are pointwise Lipschitzian. For concave utility functions, demand is differentiable almost everywhere in the case of differentiable additively separable utility or in the case of quasi-linear utility.

On the consistency of arbitrary money-demand functions with the Sidrauski and the shopping-time models

This paper investigates which properties money-demand functions have to satisfy to be consistent with multidimensional extensions of Lucasí(2000) versions of the Sidrauski (1967) and the shopping-time models. We also investigate how such classes of models relate to each other regarding the rationalization of money demands. We conclude that money demand functions rationalizable by the shoppingtime model are always rationalizable by the Sidrauski model, but that the converse is not true. The log-log money demand with an interest-rate elasticity greater than or equal to one and the semi-log money demand are counterexamples.

Three essays on local demand for public services

Local provision of public services has the positive effect of increasing the efficiency because each locality has its idiosyncrasies that determine a particular demand for public services. This dissertation addresses different aspects of the local demand for public goods and services and their relationship with political incentives. The text is divided in three essays. The first essay aims to test the existence of yardstick competition in education spending using panel data from Brazilian municipalities. The essay estimates two-regime spatial Durbin models with time and spatial fixed effects using maximum likelihood, where the regimes represent different electoral and educational accountability institutional settings. First, it is investigated whether the lame duck incumbents tend to engage in less strategic interaction as a result of the impossibility of reelection, which lowers the incentives for them to signal their type (good or bad) to the voters by mimicking their neighbors’ expenditures. Additionally, it is evaluated whether the lack of electorate support faced by the minority governments causes the incumbents to mimic the neighbors’ spending to a greater extent to increase their odds of reelection. Next, the essay estimates the effects of the institutional change introduced by the disclosure on April 2007 of the Basic Education Development Index (known as IDEB) and its goals on the strategic interaction at the municipality level. This institutional change potentially increased the incentives for incumbents to follow the national best practices in an attempt to signal their type to voters, thus reducing the importance of local information spillover. The same model is also tested using school inputs that are believed to improve students’ performance in place of education spending. The results show evidence for yardstick competition in education spending. Spatial auto-correlation is lower among the lame ducks and higher among the incumbents with minority support (a smaller vote margin). In addition, the institutional change introduced by the IDEB reduced the spatial interaction in education spending and input-setting, thus diminishing the importance of local information spillover. The second essay investigates the role played by the geographic distance between the poor and non-poor in the local demand for income redistribution. In particular, the study provides an empirical test of the geographically limited altruism model proposed in Pauly (1973), incorporating the possibility of participation costs associated with the provision of transfers (Van de Wale, 1998). First, the discussion is motivated by allowing for an “iceberg cost” of participation in the programs for the poor individuals in Pauly’s original model. Next, using data from the 2000 Brazilian Census and a panel of municipalities based on the National Household Sample Survey (PNAD) from 2001 to 2007, all the distance-related explanatory variables indicate that an increased proximity between poor and non-poor is associated with better targeting of the programs (demand for redistribution). For instance, a 1-hour increase in the time spent commuting by the poor reduces the targeting by 3.158 percentage points. This result is similar to that of Ashworth, Heyndels and Smolders (2002) but is definitely not due to the program leakages. To empirically disentangle participation costs and spatially restricted altruism effects, an additional test is conducted using unique panel data based on the 2004 and 2006 PNAD, which assess the number of benefits and the average benefit value received by beneficiaries. The estimates suggest that both cost and altruism play important roles in targeting determination in Brazil, and thus, in the determination of the demand for redistribution. Lastly, the results indicate that ‘size matters’; i.e., the budget for redistribution has a positive impact on targeting. The third essay aims to empirically test the validity of the median voter model for the Brazilian case. Information on municipalities are obtained from the Population Census and the Brazilian Supreme Electoral Court for the year 2000. First, the median voter demand for local public services is estimated. The bundles of services offered by reelection candidates are identified as the expenditures realized during incumbents’ first term in office. The assumption of perfect information of candidates concerning the median demand is relaxed and a weaker hypothesis, of rational expectation, is imposed. Thus, incumbents make mistakes about the median demand that are referred to as misperception errors. Thus, at a given point in time, incumbents can provide a bundle (given by the amount of expenditures per capita) that differs from median voter’s demand for public services by a multiplicative error term, which is included in the residuals of the demand equation. Next, it is estimated the impact of the module of this misperception error on the electoral performance of incumbents using a selection models. The result suggests that the median voter model is valid for the case of Brazilian municipalities.

The market of academic journals : empirical evidence from data on French libraries

This paper analyzes the demand and cost structure of the French market of academic journals, taking into account its intermediary role between researchers, who are both producers and consumers of knowledge. This two sidedness feature will echoes similar problems already observed in electronic markets – payment card systems, video game console etc - such as the chicken and egg problem, where readers won’t buy a journal if they do not expect its articles to be academically relevant and researchers, that live under the mantra “Publish or Perish”, will not submit to a journal with either limited public reach or weak reputation. After the merging of several databases, we estimate the aggregated nested logit demand system combined simultaneously with a cost function. We identify the structural parameters of this market and find that price elasticities of demand are quite large and margins relatively low, indicating that this industry experiences competitive constraints.

Task demand effects on postural control in older adults

The literature shows conflicting results regarding older adults' (OA) postural control performance. Differing task demands amongst scientific studies may contribute to such ambiguous results. Therefore, the purpose of this study was to examine the performance of postural control in older adults and the relationship between visual information and body sway as a function of task demands. Old and young adults (YA) maintained an upright stance on different bases of support (normal, tandem and reduced), both with and without vision, and both with and without room movement. In the more demanding tasks, the older adults displayed greater body sway than the younger adults and older adults were more influenced by the manipulation of the visual information due to the room movement. However, in the normal support condition, the influence of the moving room was similar for the two groups. These results suggest that task demand is an important aspect to consider when examining postural control in older adults. (c) 2006 Elsevier B.V. All rights reserved.

Properties advanced of the silicon nitride based ceramics and recent performance on automotive parts manufacture by machining process: Advanced Ceramics, demand Forecast

Automotive parts manufacture by machining process using silicon nitride-based ceramic tool development in Brazil already is a reality. Si 3N4-based ceramic cutting tools offer a high productivity due to their excellent hot hardness, which allows high cutting speeds. Under such conditions the cutting tool must be resistant to a combination of mechanical, thermal and chemical attacks. Silicon nitride based ceramic materials constitute a mature technology with a very broad base of current and potential applications. The best opportunities for Si3N 4-based ceramics include ballistic armor, composite automotive brakes, diesel particulate filters, joint replacement products and others. The goal of this work was to show latter advance in silicon nitride manufacture and its recent evolution on machining process of gray cast iron, compacted graphite iron and Ti-6Al-4V. Materials characterization and machining tests were analyzed by X-Ray Diffraction, Scanning Electron Microscopy, Vickers hardness and toughness fracture and technical norm. In recent works the authors has been proved to advance in microstructural, mechanical and physic properties control. These facts prove that silicon nitride-based ceramic has enough resistance to withstand the impacts inherent to the machining of gray cast iron (CI), compacted graphite iron (CGI) and Ti-6Al-4V (6-4). Copyright © 2008 SAE International.

Differential fuel taxes and their effects on automobile demand

Includes bibliography

Energy demand in soybean seeding on maize straw intercropped with forage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)